The long-term goal of the Rocky Mountain Taste & Smell Center is to gain a thorough understanding of transduction and intercellular interactions in chemosensory epithelia under normal, and disease conditions. To achieve this aim, our studies are first conducted in animal mode systems, then extended to humans when feasible. The six projects contained here, which examine both human and animal systems, are interrelated by transmission, and phenotype acquisition. In four of the projects, a primary focus is stimulus transduction. Inhibitory odorant responses and sweet taste transduction will be studied using electrophysiological and functional imaging techniques in two projects; another project will examine the role that functional changes in olfactory receptor neurons may play in steroid- dependent anosmia in humans, and finally transduction of intraepithelial chemical signals mediating development of taste buds will be studied. This last project is one of three projects which focus on development and regeneration of taste buds will be studied, the proposal's second major theme. The other two projects in this group examine synaptogenesis and synaptic specificity, and the events underlying functional and anatomical recovery of taste in humans following post-irradiation dysgeusia. The third programmatic theme involves synaptic transmission between taste receptor cells and the primary functional correlates of vesicular release of neurotransmitter from taste cells and seek to identify the neurotransmitter(s) released from taste receptor cells onto their afferent nerves. The four theme, phenotype acquisition and characterization, relates four projects. This projects will study whether the morphological and histochemical phenotypes of taste cells relate to cell lineage, relative age, state of innervation or to a functional state of the receptor cells. The projects of the Rocky Mountain Taste and Smell Center involve collaborative, interdisciplinary efforts and address several important questions in the field of chemosensory research. The shared expertise and related interests of the investigators brought together in this Center facilitate approaches to questions hitherto intractable by a single methodology or laboratory.